Target Development
Development for the SINQ High-Power
Target
High-Power Neutron
Neutron
Spallation Source
Werner
Wagner
Werner Wagner
Paul Scherrer Institut, Spallation Neutron Source Division,
Paul Scherrer Institut, Spallation Neutron Source Division,
5232 Villigen PSI, Switzerland
5232 Villigen PSI, Switzerland
Abstract.
SINQ is a 1 MW class research Spallation neutron source, driven by the PSI proton accelerator system. In
Abstract. SINQ is a 1 MW class research spallation neutron source, driven by the PSI proton accelerator system. In
terms
of
beam
power, it is, by a large margin, the most powerful Spallation neutron source currently in operation
terms of beam power, it is, by a large margin, the most powerful spallation neutron source currently in operation
worldwide.
As
a
consequence, target load levels prevail in SINQ which are beyond the realm of existing experience.
worldwide. As a consequence, target load levels prevail in SINQ which are beyond the realm of existing experience.
Therefore,
(STIP) is
is currently
currently underway
underwaywhich
which will
will help
helptotoselect
selectthe
theproper
proper
Therefore, an
an extensive
extensive materials
materials irradiation
irradiation program
program (STIP)
structural
material
and
make
dependable
life
time
estimates
accounting
for
the
real
operating
conditions
that
prevail
structural material and make dependable life time estimates accounting for the real operating conditions that prevail inin
the
is going
going on
on within
within the
the MEGAPIE
MEGAPIE (MEGAwatt
(MEGAwatt Pilot
Pilot
the facility.
facility. In
In parallel,
parallel, both
both theoretical
theoretical and
and experimental
experimental work
work is
Experiment)
project,
to
develop
a
liquid
lead-bismuth
Spallation
target
for
a
beam
power
level
of
1MW.
Experiment) project, to develop a liquid lead-bismuth spallation target for a beam power level of 1MW.
reason aa staged
staged approach
approach has
has been
been embarked
embarked upon,
upon,
reason
starting
with
a
heavy
water
cooled
rod
target
INTRODUCTION
starting with a heavy water cooled rod target ofof
INTRODUCTION
Zircaloy-2 and
and proceeding
proceeding via
via steel
steel clad
clad lead
lead rods
rods
The
PSI
accelerator
complex
provides
a
proton
Zircaloy-2
The PSI accelerator complex provides a proton
towards the
the final
final goal
goal of
of aa target
target optimized
optimized ininboth,
both,
beam
of
590
MeV
used
for
a
wide
range
of
towards
beam of 590 MeV used for a wide range of
neutronic performance
performanceand
andservice
servicelife
life time.
time.
applications.
neutronic
applications.The
The upgrade
upgrade program
program over
over the
the years
years took
took
the
100
theproton
protoncurrent
currentfrom
fromits
itsoriginal
original design
design value
value of
of 100
In its
its current
current form
form the
the SINQ
SINQ target
target isis an
an array
arrayofof
In
|iA
to
its
present
value
of
1.8
mA,
and
further
D22O-cooled
O-cooled lead
lead rods
rods in
in steel
steel cladding.
cladding.The
Therod
rodarray,
array,
µA to its present value of 1.8 mA, and further
D
upgrading
upgradingisisin
inprogress
progress [1].
[1].
shown in
in figure
figure 1,1, isis contained
contained ininaadouble
doublewalled
walledAlAlshown
shell
and
suspended
from
a
heavy
shielding
plug.
shell and suspended from a heavy shielding plug.
After
After penetrating
penetrating two
two pion
pion production
production targets,
targets,
named
M
and
E,
about
1.25
mA
(70%)
of
proton
beam
named M and E, about 1.25 mA (70%) of proton beam
are
aretransported
transported to
to the
the spallation
spallation target
target of
of SINQ with aa
computed
computedloss
lossof
ofas
as little
little as
as 10 ppm on the last 25 m of
beam
beam line.
line. Injection
Injection into
into the
the SINQ-target
SINQ-target is from
from
underneath,
underneath, keeping
keeping the
the whole
whole circumference
circumference of the
target
targetshielding
shieldingblock
block free
free for
for neutron
neutron utilization
utilization [2].
SINQ
SINQ isis optimized
optimized for
for high
high time
time average neutron
flux.
flux. Thermal
Thermal neutron
neutron beams
beams are
are extracted by beam
tubes
tubesthat
that end
end near
near the
the maximum
maximum of
of the
the thermal flux.
cold moderator
moderator system
system containing
containing 20 1l of liquid D22
AAcold
25 KK [3]
[3] serves
serves to
to slow
slow neutrons
neutrons down below
atat 25
thermal energies
energies and
and to
to supply
supply "cold"
"cold" neutrons for
thermal
seven supermirror
supermirror coated
coated neutron
neutron guides [4]. The
seven
primary mission
mission of
of SINQ
SINQ is
is to
to supply a suite of
primary
neutron scattering
scattering instruments
instruments serving
serving a variety of
neutron
researchfields
fieldsof
of current
current interest.
interest.
research
FIGURE
FIGURE 1.1. The
The rod
rod array
array ofof the
the target
target Mark
Mark33used
usedinin
SINQ.
Neutronic calculations
calculations for
foraavery
verydetailed
detailed model
modelofof
the moderator tank
tank and
and the
the target
target system
system were
were made
made
using the LAHET-MCNP
LAHET-MCNP code
code system
system[5].
[5].Comparing
Comparing
the results of
of the
the flux
flux calculations
calculations for
fordifferent
different target
target
types envisaged
envisaged (figure
(figure 2)
2) one
one finds,
finds, asasexpected,
expected,that
that
Zircaloy
Zircaloy tube
tube cladding
cladding gives
gives the
the highest
highest neutron
neutron flux
flux
for
for aa solid
solid lead
lead target.
target. For
For aa liquid
liquid Pb-Bi-target,
Pb-Bi-target, aa
further,
quite
significant
flux
increase
is
expected.
further, quite significant flux increase is expected.
THE SINQ-TARGET
SINQ-TARGET DEVELOPMENT
DEVELOPMENT
THE
PROGRAM
PROGRAM
terms of
of beam
beam power,
power, SINQ
SINQ is,
is, by
by aa large
large
InIn terms
margin, the
the most
most powerful
powerful spallation
spallation neutron
neutron source
source
margin,
currentlyin
in operation
operation world
world wide.
wide. As
As aa consequence,
consequence,
currently
target load
load levels
levels prevail
prevail in
in SINQ
SINQ which
which are
are beyond
beyond
target
the
realm
of
existing
experience,
demanding
a
careful
the realm of existing experience, demanding a careful
approach
to
the
design
and
operation
of
a
high
power
approach to the design and operation of a high power
target.
While
the
best
neutronic
performance
of
the
target. While the best neutronic performance of the
source
is
expected
for
a
liquid
lead-bismuth
eutectic
source is expected for a liquid lead-bismuth eutectic
target,no
noexperience
experiencewith
with such
such systems
systems exists.
exists. For
For this
target,
this
The
The SINQ
SINQ Target
Target Irradiation
Irradiation Program
Program
Many
Many of
of the
the questions
questions relating
relating toto the
the life
life
expectancy
expectancy of
of different
different target
target concepts
concepts can
can only
only bebe
answered
answered by
by irradiation
irradiation under
under realistic
realistic conditions.
conditions.
Therefore
materials
testing
samples
Therefore materials testing samples from
from different
different
materials
materials and
and of
of different
different shapes
shapes (tensile
(tensiletest,
test,bending
bending
CP642, High Intensity and High Brightness Hadron Beams: 20th ICFA Advanced Beam Dynamics Workshop on
High Intensity and High Brightness Hadron Beams, edited by W. Chou, Y. Mori, D. Neuffer, and J.-F. Ostiguy
© 2002 American Institute of Physics 0-7354-0097-0/02/$ 19.00
119
fatigue,
SANS samples,
samples, Charpy
Charpy test
test etc.)
etc.)
fatigue, TEM-disks,
TEM-disks, SANS
were
embedded
in
the
SINQ
targets
(Mark
2
and
3)
fatigue,
TEM-disks,
SANStargets
samples,
Charpy
test3)etc.)
were
embedded
in the SINQ
(Mark
2 and
inin
the
framework
of
an
international
collaboration
(STIP)
were
embedded
in
the
SINQ
targets
(Mark
2
and
3)
the framework of an international collaboration (STIP)in
[6].
The
aim
program
is to
to examine
examine
theeffect
effect
an international
collaboration
(STIP)
[6].the
Theframework
aim of
of the
theofprogram
is
the
ofof
the
realistic
SINQ
operating
conditions
on
a
variety
[6].
The
aim
of
the
program
is
to
examine
the
effect
of
the realistic SINQ operating conditions on a variety ofof
different
candidate
structural
and
solid target
target
materials
the realistic
SINQ
operatingand
conditions
on amaterials
variety of
different
candidate
structural
solid
different
structural
and solid
target materials
for
other
future
spallation
targets.
for SINQ
SINQ and
andcandidate
other future
spallation
targets.
There were
were several
severalrods
rodsinspected
inspectedbybyneutron
neutron
There
radiography.
One
interesting
result
is
shown
There were
rods inspected
neutronin in
radiography.
Oneseveral
interesting
result is byshown
Figure
5.
radiography.
One
interesting
result
is
shown
in
Figure 5.
Figure 5.
for SINQ and other future spallation targets.
Performance
different target
target materials
materialsunder
underSINQ
SINQconditions
conditions
Performance comparison
comparison for
for different
(calculations with the code LAHET)
!!!!!!!!!!
!!!!!!!!!!!!!!!comparison
!!!!$iu
$!for
i§idifferent
^
Performance
target materials under SINQ conditions
(calculations with the code LAHET)
2.5
Zr rods
Zr rods
Pb + steel cladding (0.5
mm)Pb + steel cladding (0.5
2
0 10
10 20
50 mm
mm
50
Pb-Bi
20 30
cold
0
0
Pb-Bi
30 40
source
cold
source
0.5
Pb + Zr cladding (0.7 mm)
beam tubes
0
1
mm)
Pb + Zr cladding (0.7 mm)
beam tubes
0.5
1.5
target region
1
2
target region
1.5
thermal flux [rel. units]
thermal flux [rel. units]
2.5
40
50 50
60 60
70 70
80 80
9090
FIGURE
aluminium
safety-hull
FIGURE
Thewindow
windowof
aluminium
safety-hull
FIGURE3.3.3. The
The
window
ofofthe
thethealuminium
safety-hull
ofof of
target
discs
from
it. it.
Adapted
target
Mark-2after
aftercutting
cuttingseveral
severaldiscs
discs
from
Adapted
target Mark-2
Mark-2
after
cutting
several
from
it.
Adapted
from
from[2].
[2].
from
[2].
100
100
radialradial
position
[cm][cm]
position
FIGURE
2. Calculated
Calculated
radial
flux
distribution
FIGURE
2.
Calculated
radial
flux
distributionin
theSINQ
SINQ
FIGURE
2.
radial
flux
distribution
ininthe
the
SINQ
moderator
for
different
options
of
rod
targets
and
a
moderator
for
different
options
of
rod
targets
and
liquid
moderator for different options of rod targets and aaliquid
liquid
PbBiPbBi
target.
target.
PbBi
target.
120
25
2
25
2
1.0x10
p/m
1.0x10
p/m
25
2
25
2
2.9x10
2.9x10p/mp/m
300
300
25
25
250
Stress
[MPa]
Stress
[MPa]
In target
Mark
2 there
were10
rodsholding
holdingtest
test
In target
target
Mark
22 there
were
In
Mark
there
were
1010rods
rods
holding
test
specimens
(altogether
about
1500),
some
containing
specimens
(altogether
about
1500),
some
containing
specimens (altogether about 1500), some containing
thermocouples
to
monitor
irradiationtemperature.
temperature.
thermocouples
to
the
irradiation
thermocouples
to monitor
monitor
thethe
irradiation
temperature.
Also
dosimetry
packages
were
placed
with
the test
Also dosimetry
dosimetry packages
Also
packages were
were placed
placed with
with the
the test
test
specimens.
The
temperaturesof ofmost
mostofofthe
thetest
test
specimens.
The
temperatures
specimens.
The
temperatures
of
most
of
the
test
specimens
were
in the
range
of
250
to400
400°C.
°C.During
During
specimens
were
in
the
range
of
250
to
specimens
were in
the range
of
250– toDec.
4001999),
°C. During
its operation
period
(June
1998
target
its operation
operation
period
(June
1998
-– Dec.
1999),
target
its
period
(June
1998
Dec.
1999),
target
Mark
2 has
been
charged
with
6800
mAhofofprotons.
protons.
Mark
2
has
been
charged
with
6800
mAh
Mark
2 has
been
charged
with 6800
mAh ofproduction
protons.
peak
radiation
damage
andhelium
helium
TheThe
peak
radiation
damage
and
production
Thewere
peak12.5
radiation
damage
and
helium
production
appm
steel,
respectively.
were 12.5 dpadpa
andand
850850
appm
in in
steel,
respectively.
were 12.5 dpa and 850 appm in steel, respectively.
follow-up target (Mark 3 cf. figure 1), was
TheThe
follow-up
target (Mark 3 cf. figure 1), was
The
follow-up
targetway,
(Mark
3 cf. figure
1), 2000
was
equipped
in a similar
including
more than
equipped in a similar way, including more than 2000
specimens.
target
received
an accumulated
equipped
in a This
similar
way,
including
more than proton
2000
specimens.
This
target
received
an accumulated
protonof
dose of This
above
10 Ah,
whichangives
a maximum
specimens.
target
received
accumulated
proton
doseabout
of above
10
Ah,
which
gives
a
maximum
of
22 dpa
inAh,steel.
Thegives
maximum
irradiation
dose
of
above
10
which
a
maximum
of
about
22
dpa
in
steel.
The
maximum
irradiation
temperature
has
risen
up to
480°C.
Among the
samples
about
22
dpa
in
steel.
The
maximum
irradiation
temperature
has
risen upintocontact
480°C. with
Among
the samples
are somehas
irradiated
stationary
liquid
temperature
riseninupcontact
to 480°C.
Among
the samples
are metal
some(PbBi
irradiated
with
stationary
liquid
and
mercury).
are
some
irradiated
in
contact
with
stationary
liquid
metal (PbBi and mercury).
metal (PbBi
and mercury).
The analysis
of the Al-Mg(3) safety-hull has been
The
analysis
the Al-Mg(3)
safety-hull
haswindow
been
performed
on of
several
discs cut from
the beam
The
analysis
of the Al-Mg(3)
been
performed
cut fromsafety-hull
the
beam has
window
(figure on
3) several
[2]. Thediscs
engineering
strain-stress
curves
performed
on
several
discs
cut
from
the
beam
window
(figure
3) [2].
The engineering
strain-stress
curves
shown
in figure
4 demonstrate:
a) significant
(figure
3)
strain-stress
curves
shown
in [2].
figure
4engineering
demonstrate:
a) irradiation
significant
hardening
hasThe
been
introduced
by
the
(as
shown
in hasfigure
4the demonstrate:
a)ductile
significant
hardening
beenb) introduced
(asat
expected);
and
materialbyis the
stillirradiation
even
hardening
has
been
the2.ductile
irradiation
expected);
and fluence
b) theintroduced
material
evenis(as
atan
the highest
of 3.1×10is25bystill
p/m
The
latter
25
2
expected);
b) the
is
still
ductile
result
for material
safety considerations
in even
relation
the important
highest and
fluence
of
3.1xl0
p/m
. The
latter
is anat
25
the
highest
fluence
ofsafety
3.1×10
p/m2. The in
latter
is an
with
theresult
target
enclosure.
important
for
considerations
relation
important
result
for safety considerations in relation
with the target
enclosure.
with the target enclosure.
350
350
2.4x10 25
p/m
250
2
3.1x10 p/m
25
2
2
2.4x10 p/m
2
3.1x10 p/m
Unirr.
Unirr.
200
200
150
150
100
100
50
50
0
-2 0
-02 0
-2
0
2
2
2
4
4
4
6
6
6
8
8
10 12 14 16 18 20 22 24
10 12 14 16 18 20 22 24
Strain
8Strain
10 (%)
12 14 16 18 20 22 24
(%)
Strain (%)
FIGURE 4. Tensile test results of samples cut from the
FIGURE
4. edge
Tensile
testthe
results
of samples
cut from the
centre and 4.
area oftest
proton beam
and unirradiated
FIGURE
Tensile
results
of
samples
cut from the
centre
and
edge
area
of
the
proton
beam
and
unirradiated
material.and
Adapted
from
[2].the proton beam and
centre
edge from
area [2].
of
unirradiated
material.
Adapted
material. Adapted from [2].
Zy tube
}
Zy tube
Zy tube
steel
}
steel Zy tube
Zy tube
steel
Zy tube
FIGURE 5. A picture of neutron radiography showing the
FIGURE
5. A
of neutron
radiographysteel
showing
the
middle part
of picture
a Zircaloy
clad martensitic
(F82H)
FIGURE
5.of
Aa picture
of neutron
radiography
middle
Zircaloy
clad martensitic
steelshowing
(F82H)the
sample.part
The
black
spots are
believed
to be hydrides
formed
middle
partblack
of
aspots
Zircaloy
clad martensitic
steelformed
(F82H)
sample.
The
are believed
to be hydrides
in the Zircaloy
cladding.
The black
spots are believed to be hydrides formed
insample.
the Zircaloy
cladding.
in the Zircaloy cladding.
WORK TOWARDS A LIQUID METAL
WORK TOWARDS
A LIQUID
TARGET FOR
SINQ METAL
WORK TOWARDS
A LIQUID
TARGET
FOR
SINQ METAL
It is now generally acknowledged that, for high
TARGET FOR SINQ
beam power and in particular for high beam power
It is now generally acknowledged that, for high
density
required
foracknowledged
efficient
flux
It power
is as
nowand
generally
that, power
for
high
beam
in particular
for highneutron
beam
beam power
and in particular
for high
beam flux
power
density
as required
for efficient
neutron
density as required for efficient neutron flux
generation, liquid metal targets are the concept of
choice. The sensitivity of SINQ to neutron absorption
in or near the target essentially limits the selection of
available target materials to lead and some of its low
melting alloys, in particular lead-bismuth.
Currently (May 2002), the MEGAPIE project
finished the engineering design phase, envisaging a
target date of January 2005 to be installed at SINQ,
followed by an approximately 9 months operational
period in the year 2005.
Corrosion and Liquid Metal Technology
(The LiSoR experiment)
CONCLUDING REMARKS
The world's most powerful spallation neutron
source is currently operated at the Paul Scherrer
Institut. While there is a potential for further increase
of the neutron flux in SINQ, which will be exploited to
improve the facility's competitiveness, running a
Megawatt class spallation facility in itself is an
important cornerstone for many development projects
in the field. Examples are MEGAPIE and PSI's input
to the target concepts of the next generation spallation
neutron sources, like ESS, SNS and JNSC. The SINQ
target development program will also benefit most
other projects in the field of accelerator application in
nuclear technology.
One of the major unknowns in liquid metal target
development is related to the question, whether liquid
metal-solid metal reactions (LiSoR) in the presence of
(static or cyclic) stress are enhanced under irradiation.
Since this is a problem that must be solved before a
liquid metal target can be irradiated in a proton beam
for an extended period of time, an experiment has been
initiated to use PSI's 72 MeV Philips cyclotron (Inj. 1)
to irradiate stressed steel specimens in contact with
flowing liquid metal. Scoping calculations showed
that, while much less radioactivity is produced, the
damage levels and gas production in thin specimens by
72 MeV protons are, within reasonable limits,
comparable to those on the inside of the proton beam
window at 590 MeV. Also, the beam parameters can
be adjusted in such a way that relevant heating rates at
the solid-liquid interface are obtained. The irradiation
program will start in June 2002. The initial program
comprises four samples of a 9Cr-lMo martensitic steel
(T91), the most promising material to be used for the
enclosure hull. The envisaged irradiation times are 10
and 20 days, respectively, at a temperature of 300 °C.
ACKNOWLEDGEMENTS
The participation and collaboration of my
colleagues Y. Dai, F. Groschel, H. Glasbrenner and E.
Lehmann is greatly acknowledged. Special thanks go
to Gunter Bauer (now FZ Jtilich) for his initiatives for
the SINQ target development program.
REFERENCES
MEGAPIE
The Megawatt Pilot Target Experiment,
MEGAPIE [7] is a joint initiative by six European
research institutions (including PSI) and JAERI
(Japan), DOE (USA) and KAERI (Korea). The aim of
this initiative is to demonstrate the feasibility of a
liquid lead-bismuth target for spallation facilities at a
beam power level of 1 MW. The goal of this
experiment is to explore the conditions under which
such a target system can be licensed, to accrue relevant
materials data for a design data base and to gain
experience in operating such a system under the
conditions of present day accelerator performance.
Furthermore, design validation by extensive
monitoring of its operational behaviour and post
irradiation examination of its components are integral
parts of the project. The activities described above
(STIP and LiSoR) are part of an extensive materials
R&D program which is carried out in order to
maximize the safety of the target and to optimize its
layout.
121
1
P. Schmelzbach "The PSI cyclotron and its extrapolation
to a 10 MW driver", this volume (2002)
2
G.S. Bauer, Y. Dai, W. Wagner ,,SINQ Layout,
Operation, Applications and R&D to High Power", Ann.
Chim. Sci. Mat. 27 (2002)
3
H. Spitzer, G.S. Bauer, T. Hofmann "First Operation
Experience with the Cryogenic Moderator at the SINQ
Spallation Neutron Source" Proc. Int. Workshop on Cold
Moderators for Pulsed Sources, Argonne, EL (1997)
4
W. Wagner, J. Duppich, Proc. ICANS XE, Rutherford
Appleton Laboratory, Report No. 94-025 (1994) I-368-I376
5
G.S. Bauer, A. Dementyev, E. Lehmann, "Target
Options for SINQ - A Neutronic Assessment" in
Proceedings ICANS XIV, ANL-98/33 (1998) 703-716
6
Y. Dai and G.S. Bauer, "Status of the first SINQ
irradiation experiment, STIP-I", J. Nucl. Mater. 296
(2001) 43-53.
7
G.S. Bauer, M. Salvatores, G. Heusener, MEGAPIE, a
1 MW pilot experiment for a liquid metal spallation
target J. Nucl. Mater. 296 (2001) 17-3